The invention concerns a flowback process of the product contained in a distribution circuit of a filling machine, the distribution circuit connects upstream to a storage tank of the product up to a filling nozzle that is intended to be brought opposite the opening of a container to be filled.
This process is more especially intended to be implemented in machines that permit filling hollow containers, such as bottles or jars, with a product, for example a liquid food product.
Such machines can include a rotary carousel provided with a series of filling nozzles, each nozzle then being supplied by the distribution circuit. The containers are inserted onto the carousel at a given point of the circle that it describes that is arranged below a filling nozzle. Once the container is in place under the nozzle, the latter is supplied by product in such a way that the product is poured inside the container. When a desired degree of filling is reached, the nozzle supply is interrupted by a valve inserted in the distribution circuit and the container is then released by the carousel, of course before the carousel has perform one full turn.
In a machine in operation therefore a certain quantity of product exists permanently in transit in the distribution circuit between the storage tank and the distribution nozzle. This quantity of product increases of course with the number of nozzles that the machine carries.
However, at the time of the filling operation shutdown, when this shutdown is scheduled, for example at the end of production, or that it is unscheduled, for example when the production line experiences a problem on which the filling machine is located down stream from the machine, this quantity of product is trapped in the distribution circuit, and this trapping can last a certain time.
During this trapping the product contained in the distribution circuit can deteriorate or no longer correspond to the filling conditions as defined.
That happens, for example, in the case when the product is intended to be filled at a given temperature, either hot or cold. In effect, if the product in the storage tank is generally maintained at the good temperature, for example due to a forced circulation in a heat exchanger, such is not the case for the product contained in the distribution circuit because this latter in principle is not temperature controlled considering that, when in operation, the product is transported and resides there a very a short time.
In this way, after a shutdown of the filling machine, it is very often necessary to get rid of the product that remained in the distribution circuit. This unusable product is penalized twice, on the one hand from the fact of the material loss and on the other hand because it is necessary to plan an evacuation circuit of this material.
The invention therefore has a goal of proposing a solution permitting the resolving of difficulties linked to the presence of material in the distribution circuit at the time of filling machine shutdowns.
To this end, the invention proposes a flowback process, characterized in that it includes a stage consisting in delimiting around the nozzle, by means of a sealed protecting casing, a surrounding enclosure, and a stage during which a pressurized discharge fluid is injected into the surrounding wall, through an auxiliary port, to cause the product contained in the distribution circuit to flow back in the direction of the tank.
According to other characteristics of the process according to the invention
the discharge fluid is an inert gas; or
the discharge fluid is sterile air.
The invention also proposes a filling machine for implementing the process according to the invention, characterized in that the filling nozzle is enclosed in a casing firmly fixed to a nozzle support. The casing includes an opening opposite which the nozzle is arranged, and the casing including a mobile shut-off butterfly valve that, in a closed position, closes the opening and seals the casing, and in which the machine includes an auxiliary port that opens into the enclosure and that is intended to be connected to a source of pressurized fluid.
According to other characteristics of the machine according to the invention:
an activation device between controls the butterfly shut-off valve. its closed position and an opened position in which the opening of the casing is released;
activation devices of the shutter include a fluid pressure actuator with dual action;
the machine includes means to circulate a cleaning agent, within the casing, the cleaning agent is introduced into the casing by the filling nozzle and is evacuated through the auxiliary port that opens into the inside of the enclosure delimited by the casing;
the auxiliary port is arranged at the low point of the casing;
in the course of filling a sterile gas is injected into the casing through the auxiliary port and evacuated through the opening of the casing while surrounding the flow of the product between the filling nozzle and the container; and
the machine includes several filling nozzles each of which is enclosed in a permanent casing provided with a mobile plug permitting the casing to be sealed.